Is the Prius battery toxic?

Written by terrapass


You’re proving to be big fans of our new TerraPass Answers feature. This week’s question is from Nushin in Colorado.

> My sister in law who is an insurance company adjuster tells me that there is something toxic about the battery cell in the Prius. Is this true?

Do you know the answer? Post in the comments section below.

**Previous questions and answers**

– Is online shopping bad for the environment?
– How much efficiency do I gain with properly inflated tires?
– Should I buy a Prius

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  1. Rich Legault

    I am a Prius owner, and an Insight owner, too.
    It is my understanding that the batteries in the Prius are of the Nickel-Metal Hydride variety, NiMH. See this link for confirmation:
    That makes them completely recyclable. See this link for confirmation:
    Of course, all batteries are dangerous and toxic in that if you ate one it would probably kill you. 🙂
    Be well!

  2. Kevin Wright

    Yes, but not really. What I mean to say is that the Nickel itself in the Prius’ Nickel-Metal-Hydride (NiMH) drive battery is toxic, but on a low level. The start battery that the Prius uses is a standard car battery which is Lead-Acid. Just by the name you should understand that it is not good and is in fact much worse for the environment than the NiMH drive battery. However all cars (Tesla excluded) on the road today use this type of battery and they are strictly controlled and recycled at all mechanic facilities.
    If you are worried about the Prius battery buy a Honda Fit, Nissan Versa, Mini, or the forthcoming Ford Fiesta for a car with very good fuel economy and reasonable space. Otherwise realize that the Prius is a mainstream car with excellent economy and is extremely safe as well.
    While I do not own one, the Prius is an excellent car. I personally would rather have something else, but owners seem to be very satisfied with theirs.

  3. Craig Hunter

    Fire departments do consider the batteries of all hybrids to be toxic, not just the Prius. All fire departments have special protocols in dealing with hybrid accidents; here is a sample.
    Hybrid vehicles also require special handling when dismantling and disposing of spent batteries due to their toxic nature. Though substantially less toxic than conventional car batteries, nickel-based batteries are known carcinogens and there are concerns about the environmental impacts of nickel mining which create their own problems.
    Here is Toyota’s own word on emissions with their ISO ratings. Note that most emission ratings are higher in the Prius than gasoline powered vehicles, with exception only to the driving cycle.
    All in all we are not saving the planet by driving a hybrids or fully electric vehicles, we are merely treading less heavily on the environment.

  4. Donny

    Good info. I’ll expand on what Craig said: all batteries are toxic, but standard car batteries are more toxic (being lead-acid) that hybrid batteries (being nickel-based).
    And yes, absolutely, no _car_ will save the world. A car is made out of metal mined out of the ground and plastic (from oil) pumped out of the ground, both at environmental expense.
    The car is then filled with nasty things like oil, transmission fluid and brake fluid, some amount of which always ends up leaking into our water.
    Finally, every couple of weeks, the car is filled with refined oil (gasoline) for the purpose of burning it, yielding emissions and greenhouse gases.
    But the reason folks are so excited about hybrids, IMHO, is that they finally represent a step in the right direction for the auto industry, after literally decades of running as fast as possible in the wrong direction environmentally. There are downsides to all technologies, but the downsides on the hybrid battery appear to be relatively small.

  5. veek

    A non-toxic battery, like Journalistic Integrity, or Jumbo Shrimp, is an oxymoron.
    A good bumper sticker for the Prius (or any similar auto) might be “My Car Is Probably Destroying The Planet More Slowly Than Your Car.” When we drive somewhere we should be aware that we are not directly helping the environment.

  6. Michelle

    I thought the battery issue was more about getting the nickel to put into the battery. I was told the nickel is from a mine that has an enormous dead zone surrounding it due to the pollution from the mining and the nickel itself. Then it has to be sent to one country to get processed, another to be processed differently, sent to japan to become a battery and then back to the states to be put in the car. It was my understanding that THIS is where the NiMH batteries were most eco-UNconscious.
    If anyone knows, please post! I’d love to know if this is fallacy!

  7. Craig Hunter
  8. Michelle Vadeboncoeur

    There’s a lot of myth, urban legend, and misinformation out there on hybrid vehicle batteries and vehicle production, thanks to a flawed marketing paper by CNW and a poorly researched student newspaper article that keep getting quoted…
    Anyhow, I suggest reading:
    Hummer versus Prius: “Dust to Dust” Report Misleads the Media and Public with Bad Science:
    Prius Versus Hummer: A Nickel for Your Thoughts:
    “I read an article stating the Prius has a worse impact on the environment than a Hummer because of the enormous pollution created in making the car’s batteries. True?” :
    Prius Versus HUMMER: Exploding the Myth:
    Giving Directions: No, the Hummer Actually Isn’t More Energy Efficient Than A Prius, Let’s Put This “Debate” To Rest:
    Dust in the Wind: Hybrids’ Total Energy Cost:
    Hybrid Battery Toxicity:
    Heard the One About the Hummer?:
    Usually the mythic “article” from The Mail on the nickel in the
    hybrid cars’ NiMH batteries is quoted from a now retracted article.
    The retraction that clears up this bit of misinformation is at:
    (They were using data from the early 1970’s about the INCO-Sudbury nickel mine, which was more than 20 years before the first hybrids needed NiMH batteries, and the plant has greatly cleaned themselves up and reforested the area since then. If you were to add up the amount of nickel in the million+ hybrids sold since 1997, the total is still less than 1% of the world’s annual nickel production (far more nickel is used for stainless steel, for example).)
    Here’s the 2004 Toyota Prius Green Report (life cycle assessment):
    (you’ll need to download the Japanese fonts for your PDF reader in order to read it, but the entire document is written in English.)
    Over the lifespan of the Prius, when compared to a comparable mid-sized gasoline vehicle, the Prius comes out ahead in the life cycle assessment (LCA) for airborne emissions for CO2, NOx, SOx, HC, but actually does worse for PM (thanks to the material and vehicle production stages). Measured lifespan is given as 10 years use/100,000km. The CO2 break-even point for the 2004 Prius compared to this unnamed gasoline vehicle is given at 20,000km. (more CO2 is emitted during Prius production, but the Prius makes up for it over it’s driven lifetime.)
    Another neat thing is that the Prius is one of the first uses of Toyota’s Eco-Plastic (plastic made from plants, as opposed to petroleum products). The battery is recycleable (NiMH), as is much of the car (steel and aluminum body, for example).
    As for the batteries themselves:
    The lead-acid (Pb-A) 12v accessory batteries in hybrids tend to be smaller than those found in every traditional gasoline vehicle. Recycling programs are in place for traditional lead-acid batteries.
    All the hybrids on the market use NiMH (Nickel-Metal Hydride) batteries, which contain no heavy metals (so they’re not hazardous waste, like the Pb-A batteries), and are easily recycled.
    The hybrid battery packs in the Prius have labels on them for whom to contact to recycle them. See the HV Battery Pack Recycling section in the Prius Emergency Response Guides.
    page 11 (of the printed version):
    page 19 (of the printed version):
    (and before someone asks:
    Why did Toyota publish an “Emergency Response Guide” for its hybrid vehicles which details recommended safety procedures at the scene of an accident?
    Toyota published the “Emergency Response Guide” to address the fact that hybrid technology is new and may be unfamiliar to safety professionals. The guide provides instructions on the safe handling of our hybrid vehicles at the scene of an accident.
    Powered by both a conventional gasoline engine and an electric motor, our hybrid vehicles feature a high-voltage battery pack. Numerous safeguards have been designed into the hybrid system to help ensure that this high-voltage battery pack is kept isolated from contact with anything other than the hybrid propulsion system, in normal, as well as abnormal conditions, such as at the scene of an accident.
    To quote Toyota’s press release:
    How long does the Prius battery last and what is the replacement cost?
    The Prius battery (and the battery-power management system) has been designed to maximize battery life. In part this is done by keeping the battery at an optimum charge level – never fully draining it and never fully recharging it. As a result, the Prius battery leads a pretty easy life. We have lab data showing the equivalent of 180,000 miles with no deterioration and expect it to last the life of the vehicle. We also expect battery technology to continue to improve: the second-generation model battery is 15% smaller, 25% lighter, and has 35% more specific power than the first. This is true of price as well. Between the 2003 and 2004 models, service battery costs came down 36% and we expect them to continue to drop so that by the time replacements may be needed it won’t be a much of an issue. Since the car went on sale in 2000, Toyota has not replaced a single battery for wear and tear.
    Is there a recycling plan in place for nickel-metal hydride batteries?
    Toyota has a comprehensive battery recycling program in place and has been recycling nickel-metal hydride batteries since the RAV4 Electric Vehicle was introduced in 1998. Every part of the battery, from the precious metals to the plastic, plates, steel case and the wiring, is recycled. To ensure that batteries come back to Toyota, each battery has a phone number on it to call for recycling information and dealers are paid a $200 “bounty” for each battery.
    And Toyota recently dropped the price of replacement hybrid batteries, and is working on refurbishing them in the US:
    And I’ll note that even when considering the emissions of the fuel source and that of manufacture, the Toyota Prius came in 2nd for Greenest Vehicles of 2008 among US models in the American Council for an Energy Efficient Economy’s (ACEEE) Green Book, behind the Honda Civic GX.

  9. Leslie

    As a Prius owner and a waste reduction specialist for a local govt agency, I asked many questions and tried to cover this issue before purchasing my 2005. The dealer told me at that time they hadn’t had any failed Prius batteries returned but that the internal Toyota system was set up to send them back to the manufacturing source for recycling. They would be taken apart and each component recycled according to the applicable govt regulations. My battery hasn’t failed so I haven’t asked the questions again. But I do know that in addition to getting an average in-town/out-of-town 49+ mpg, my car emits a fraction of the greenhouse gasses other cars emit. I’m feeling as though I’ve made the best choice possible for now! Thanks to all for being concerned.

  10. Bob Wilson

    The Prius traction battery uses a concentrated, potassium hydroxide electrolyte that I’ve had on my fingers. It feels slippery because it converts fats into soap. It should be treated with respect as it will dissolve organic material such as paper, carpets, and most metals. Potassium hydroxide like sodium hydroxide have also beens sold as drain cleaners in grocery stores.
    One of the two electrodes is nickel with a thin layer of nickel hydroxide. Nickel is one of the key ingredients in stainless steel because it is so resistant to corrosion.
    The other electrode is a rare earth, hydride. A spongy mass, it holds hydrogen when the battery is charged and releases hydrogen during discharge.
    If you scan down my URL you’ll see pieces of the battery and how I ‘decapitated one’ to get at the guts. Because it is liquid starved cell, the electrolyte doesn’t really ‘run’ but kinda creeps out, very slowly.
    The chief hazard is getting the electrolyte in your eyes (touch and then rub eyes) or other soft tissue. When you touch it, just wash your hands in water and the problem is solved. If it spills on steel or other organic material, wipe and wash it up quickly as it really is a good drain cleaner.
    Now if you happen to have a used Prius battery and are worried about what to do with it, contact me. I’m paying $250 for any within 300 miles of Huntsville AL. I take them home and refurbish them to like-new status.
    If you plan to refurbish a Prius battery, contact me because you need to do it right from the beginning. This means attention of details and using a ‘smart’ charger, not something cobbled together.
    Bob Wilson

  11. den fyske

    Yes I would like to know more about where to get the charger and so forth. I am sure one jugles the modules untill one ends up with a working pack again from modules from other used packs. If one aquires enough used ones he can keep making ones that work. I am an EE so you can be as detailed as you wish.
    Den Fyske

  12. Bob Wilson

    Hi Den,
    I’ve added a URL to my battery page (a bit large) as an initial data dump. I’m using an RC hobby charger, the MRC 989, that can handle up to four modules at one time. Normally, I’m using it for single modules, to measure their capacity.
    I would recommend heading over to GreenHybrid dot com or PriusChat dot com, the areas I tend to hang out in for more follow-up. You are right that matching the modules is important but the water loss appears to be fairly even across all modules. Replacing the ‘outlier’ modules turns out to be just shifting the bar and the next weakest modules soon fail.
    NOTE: I’m not trolling for users at these site but that is where technical discussions about Prius batteries tends to occur with the experts.
    Bob Wilson

  13. Anonymous

    Any rechargable battery needs to be recycled and not just discarded into a landfill where it can leach toxic substances. Just make sure you verify that your mechancic or dealer is recycling! By the way, the same holds true for TV’s computers and other electronics.

  14. Bob Wilson

    Actually recycling is not such a good idea compared to a better answer, refurbishment. We have found that NiMH batteries lose their water, a critical part of their electrolyte. What we need are batteries that can have water replenishment.
    Toyota has already figured out this answer and I for one have successfully done it. But we are dealing with batteries designed in such a way that replenishment of the water is nearly impossible.
    Consider grocery stores and how you bag your groceries. You can use plastic, paper, or bring your own cloth. Plastic and paper bags are nearly impossible to reuse except to line waste baskets. But the cloth bag can be used time and time again. That is the type of NiMH battery we need.
    Bob Wilson

  15. Jon

    I don’t see hybrids as a step in the right direction, but rather the other way. Just as they have banned two stroke engines which are now capable of producing more power with less emissions than four strokes adding batteries to a gas cars just uses more resources than gas alone. Marketing, “the Green movement”, has got people spending money for useless vehicles that do nothing to help the environment and in fact cause more problems. In addition to the normal mining of metal, refining of oils, etc.. in car manufacturing, now they must mine the nickel and other chemicals and elements to make the additional batteries and then ship them across the world where they can be installed and then shipped out. Financially and environmentally Prius batteries are wasteful. And electric cars will never prevail. Porsche’s first car was electric and proved useless since it provided no heat, ac, or other accessories needed while driving through Europe. Hydrogen is the only way to go and to make H2 requires much energy which can only be acquired by going back to nuclear which is now the cleanest source of energy on the planet since all “waste” can now be recycled and there are no emissions. Solar requires panels that are expensive and their production is not very “green” and wind requires turbines that use petroleum products for lubrication in addition to the cost and environmental impact not to mention the thousands of birds they kill.
    [Ed. — thanks for bringing attention to the critical wind turbine lubricant problem. Who will protect us from the scourge of wind turbine lubricant?]

  16. Marcus Pederson

    The “dead zone” is a thing of the past. Just do a search on “Sudbury Reclamation”. Very interesting how many assume nickel mining has not cleaned up its act. From an informed present day view, the Prius batteries are really not at fault. Toyota only uses about 1% of the nickel mined yearly. Remember nickel is used in many, many everyday items.

  17. Anonymous

    How are the batteries recycled in a way that they are not harmful to the enviorment? Where do they go and what do the mechanics do with them? It is hard to imagine that there is any safe place you can put a toxic and poisonous battery like that.